Casting ingots



Jan. 2, 1945. A. R. ROWE- cAsTING'INGoT Filed March 28, 1944 5Sheets-Sheet, 1

LVITNESJ'ES da @0&2

BYF

INV ENTOR. ,4A/DREW P. Poe-ere,

Jan. 2, A1941's. A R 'R0WE 2,366,2"89

CASTING INGoT Filed March 28, 1944 3 Sheets- Sheet 2 Jan. 2, 1945. A, R,ROWE 2,366,289

CASTING INGOT Filed March 28, 1944 s sheets-she'et s INVENTOR.Jfrwins-5.15.5. 4 14A/025m' A. PorL-r Patented Jan. 2, 1945 36am -lCASTING'INGOTS Andrew R. Rowe, McKeesport, Pa., assignor toHarbison-Walker Refractorles Company, Pitts' burgli, Pa., a corporationof Pennsylvania Application March 28, 1944, Serial'No. 528,389

(ci. 22gim 12 Claims.

This invention relates to the casting of metallic A ingots, and thisapplication is a continuation in part of my copending application SerialNo. 498,- 940, filed August 17, 1943.

The `invention is applicable particularly to the casting of ingots ofiron and'steel, for which reason it will be described with particularreference thereto by way of illustration, but not of limitation. Thecommon practice in the casting of such ingots is to teem the molds f roma ladle which isusually of large capacity and from which the molteimetal is discharged through a relatively large nozzle so that a largestream of molten steel enters the mold under a considerable head. 'I'hisis disadvantageous for various reasons. Thus, the relatively great headof the metal causes the stools or the bottoms of the molds to be cut outrather rapidly causing diillculty in removal of the ingots, i. e.,so-called stickers, and necessitating premature discarding o-f themolds. Also, it4 produces considerable splashing which may form. ascabby surface on the ingot and thus result in defects in the surface ofproducts wrought from it or necessitate chippingthe ingot with addedexpense. Particularly, the metal in the mold is churned vigorously anddeeply by the en tering stream so that slag and other non-metallicmaterial together with gases released from the metal are forcedthroughout the body of the metal within the mold. Such materials may nothave suiilcientl buoyancy to rise to the surface so small streams themetal would enter the mold under a relatively slight head and would notcut out the stool, splash objectionably, or penetrate the cast metaldeeply, thus permitting gases to escape freely and slag or the like tocollect at' the surface rather than being churned throughout the metal.Furthermore, it was intended that the float member should rise withinthe feeder as it was lled.

Experience showed that the hot top of that patent could performsatisfactorily with som'e classes of steels or under some conditions,but

that it was open to serious disadvantages and drawbacks. One of the mostserious of those was due to the fact that the float seated closelyagainst the supporting flange of the feeder so that, particularly withordinary low silicon steels, the float tended to freeze into place inthe bottom of the hot top due to the factthat the metal would enter andfreeze between the sides of the float and the hotl top walls. Drainagearound the side of the float was not contemplated. l 'I'his thatundesirable non-metallic matter and blow i holes will be present in theingot.

Another diiilculty encountered in ordinary casting practice is that ofpipe formation. To avoid this it is customary to provide the mold witha. hot top, or feeder, which in any `of its conventional formsconstitutes an extension of the mold that acts as a reservoir for a.body of the molten metal to feed the ingot as it freezes and thus toavoid piping by filling the axial shrinkage cavity. Such' hot tops donot, however, avoid the foregoing disadvantages of pouring practicebecause vthe metal is teemed directly from the nozzle through the feederinto the mold.

In my Patent No. 1,399,798, granted December 13, 1921, I disclosed ameans whose object was to reduce the foregoing difficulties anddisadvantages. In accordance with that invention, a hot top. or feeder,member was provided around its lower end with an inwardly projectingange which acted as a continuous iloat. Either the float or the flangewas perforated. The underlying concept was that by breaking up thenozzle stream into a plurality of condition was aggravated where themetal teemed was on the low side of the pouring temperature range. Also.as the metal ran through the holes in the float member, it apparentlycreated a downwardly acting suction which tended to 'hold the floatmember in place. Even though gas escaped freely and slag or the likerose to the metal surface, this tendency for the float to stay or freezein the bottom of the hot top was objectionable because the hot top andfloat would break off during and interfere with rolling, and this wasaggravated where the perforations were in the shoulder because it thenhad to be of considerable width. The small clearance between the floatand the hot top walls or its seat prevented successful dislodging of thefloat by means of a bar or-lever. Other disadvantages were that if theladle was not spotted accurately the stream from the nozzle would tendto pass directly through .one of the holes through the plate or l lug sothat the metal would enter the moldv under seat for a refractory thegreater part of its normal head pressure, thus partially defeatingthe'aim of the invention, and also that stickers were commonlyencountered. Forthese and related reasons -the hot top of that patentdid not satisfactorily achieve its objects under the conditions whichprevail in ordinary steel mill practice and therefore it was not adoptedcommercially. f .l

, In my above-identified copendlng application I have disclosed andclaimed a method of and means for reducing or eliminating the troublesencountered with the hot tops of that patent. In

' mold with a hottop.

" before it joins the main body in theaccordance therewith the hot topand float member are so contructed that the metal poured into the hottop enters the mold by flowing around the edges of the float plate andbetween the plate and its supporting flange, or shoulder.` That is,

an imperforate float plate is used which is substantially smaller inarea than the crossv sectional area of the hot top. and it is supported,as in the patented invention, by a continuous shoulder, or flange, atthe bottom of the hot top. Either or both the plate and the shoulder maybe provided with means for metal to flow into the mold from the spacebetween the edges of the plate within the mola sc that slag and the likeis not and the hot top walls. Thus, either or both may be grooved, theplate may be supported by bosses which space it from the flange, or theshoulder along each wall may slope downwardly from each side.

Experience with the hot tops of the foregoing application in the castingof steel ingots in commercial practice has shown that theysatisfacentrapped within the body of the metal but rises freely to thesurface, and pipe and blow hole formation together with rapid cuttingout of the stool and production of scabby or cracked surface arereduced. or avoided, and which avoids Asplashing in and from thehot topduring pourifet another object is to provide an ingot hot top having afloat member which cooperates to break up the ladle stream forattainment of the foregoing objects but which'does not have the tendencyto cause slashing or to be frozen in place which characterized former.hot tops provided with float members.

Other objects will be understood from the following description.

The invention may be described inconnection with the accompanyingdrawings in which Fig. 1 is a vertical sectionalview through thepreferred 'embodiment applied to a small-end-up torily improve thesurface quality Aof ingots,

' greatly reduce cutting out of the stools or mold bottoms and theproduction of stickers, efilciently avoid the troubles encountered withordinary hot tops, produce ingots of superior quality as compared withingots poured with ordinary hot tops and as compared with those' ofmyaforesaid patent, and are of general utility. even with the common lowsilicon steels.

However, the casting of large vsize ingots with the hot tops of thatapplication has shown that although they function satisfactorily, asJust stated, they are open to disfavor because of one result inherent intheir construction. Thus, the

hot tops and floats have been constructed to pro-l vide for readydrainage. of metal, to. insure against thefreezing ofthe floats whichwas encountered with the-patented construction. Experience vhas shownthat the metal ilows so quickly into the mold through the passageway inmold; Fig. 2 a plan view of the hot top shownin Fig. 1, without the oat;Fig. 3 a fragmentary showing -on an` enlarged scale of a portion of Fig.1; Fig. 4 a view similar to Fig. 1 showing the condition afterbackpouring; Fig. 5 a vertical sectional view of a modified form of 'nottop; Fig. 6 a view similar to Fig. 3 of a portion of Fig. 5; Fig. 'Z aview similar to Fig. 5 showing another modified form of thehot'topsprovided by the invention; Fig. 8 aplan -view of Fig. '1; Fig. 9 a.'lview similar to Fig. .5 of another form, .taken on line4 III-IX, Fig.l0; Fig. 10a plan view of the *hot top of Fig. 9; .and Fig. 11aperspectlve of belng broken away ber'provided at its lower end with aninterior which the space vbetween the bottom of the plate,

or float member, and the nange is greater than v that between the plateedgeand hot top walls, .that n'o pool of metal accumulates in the hottop until the metal level reaches the oat. Consequently, up to that timethe stream of metal from v plate and causes splashing of metal.. This isobjectionable for two reasons. First, the splashing of metal from the'hot top creates a serious hazard to the operators on the pouringplatform. This necessitates the use of a -longer hot top than would beneeded otherwise for some purposes. Second, splashing within the hot topmay of the plate and the hot top walls to insure that the plate willrisefreely when the ingot is backpoured.

n is among the objects orfana mvenacn to provide ingot casting meanswhich'avoids or rethe. ladle irnpinges'continuouslv upon the floatshoulder for supporting afloat plate of su'ch vsize 'as to have itssidesspaceda substantial distance from the. walls of the hot top toprovide a passageway for metal. As in the earlier, application also,means are provided whereby the metal `can ow from the saidpassageway-and enter the mold l in the form of small streams or sheetsfrombetweenthe plate and its supporting shoulder. In

this invention. however,v the construction is such that. the flow ofmetal from the passageway between the sides of the float and the hot topwalls is throttled, to slow down drainage of metal from the saidpassageway. In this manner I amv I enabled to maintain the substantialspace around the oat plate that is necessary to avoid its being" frozenat the bottom of the lhottop while at the same time causing a pool ofmetal to form in the hot top during teemingand thereby reducing ord'uces substantially .the troublesA and disadvantages described above.

A particular object is to provide'an ingot feeder, or hot top, and thecombination of an ingot which satisfactorily breaks up the stream ofmetal entering/the mold in such manner as to permit escape of gas fromthe metal mold and to avoid strong agitation of the body of metal `into,that between the bottom ofthe eliminating splashing.4 This canbeaccomplished in various ways. most-suitably by providing either theplate or. the supporting shoulder of the hot top with spaced bosseswhich support' the plate with its lower edges spaced from the shoulder adistance less than that between the sides of the plate and the hottopwalls, whereby to throttle. the flow of metal from the latter passagewayPlate' and the shoulder. 1 Having reference now to. the drawings, Fig; 1

shows a feeder inl accordance with the invention 4associated lwith asmall-end-up mold l.

The

feeder comprises a tubular hot top member I,

made from fire clay or other refractory material, l which may take anyof a variety of forms and be supported on or by the mold in a varietyof'ways 'port the hot top, i. e., the lower ends of ribs 3 rest upon thetop of the mold and support the hot top properly positioned with respectto the mold opening. At its lower end the hot top is provided with acontinuous inwardly extending flange 4 whose upper surface slopesinwardly and downwardly, as seen in Fig. l.

` to the bottom of the hot top that was encoun-- tered with the floatsof my said patent is -over- Disposed within thehot top is a refractoryim- I perforate float plate 5 which, as shown in Figs. 1 and 3, is ofsuch size as to provide a clearance space a of substantial width betweenits edges and the hot top walls. The space a provides a passageway forescape of metal teemed into the hot top from the nozzle 6 of a ladle,not shown.' Thus,

metal passed into the feeder flows over plate 5 and passes into theclearance space a.

To provide for flow of metal into the mold plate s rests on bosses 1formed with shoulder 4 with their top surfaces above theplane f theshoulder, as seen particularly in Fig. 1. In accordance with theinvention these bosses support the plate with its lower edges spacedfrom the underlying shoulmold @I in the manner shown in Fig. l. Metal isthen teemed into the hot top from the nozzle 6. The large stream underits normal head strikes plate 5 and flows outwardly thereover to enterthe clearance space a between the edges of the der by a distance b whichis less than the width a plate and the walls of the hot top whence itdrains in relatively thin sheets 8 into the mold. A primary action isthat the breaking up of the main stream 9 of the metal by plate 5 into arelatively thin layer which moves over the plate permits at least someportion of gas carried by the metal to escape before the metal entersthe mold. This action is further enhanced by the passage of the metalfrom the feeder in thin sheets, which permits a more ready escape of gasthan is possible 'from the large stream 9. 'I'he small streams, orsheets, 8 do not churn up the body of metal I 0 within the mold so thatthere is little tendency for gas bubbles to be stirred in to the metalas it rises within the'mold. Thus, the feeder acts to reduce oreliminate blow hole formation both by freeing much of the gas carried bythe metal before it reaches the main body in the mold, and also byeducing or eliminating churning of the main ody.

Furthermore, streams 8 drain into the mold under a'pressure headthatgis? substantially less the surface of the body of metaly I0 withinthe mold, as shown in Fig. 4. When the metal between the hot top and themold wall has frozen further metal is poured into the hot top to fill itand provide a reservoir I2 (Fig. 4) of molten' metal for feeding theingot as solidication progresses, to reduce or eliminate piping.

A major advantage of the present invention, as in the case of that of mycopending application, is that the tendency of the float member tofreeze come. D

Of primary importance, however, is the throttling action of therelationship described. Thus, the metal flows over plate 5 and entersthe relatively wide space a, which may be, for example, 5A; or 1% inchwide. Flow of metalfrom a is retarded, however, by the fact that space bis smaller. This results in promptly building up a pool II of metal inthe hot top, which eliminates, or substantially so, splashing in andfrom the hot top. At the same time the width of dimension a needed toavoid freezing of the plate to' the hot top bottom is maintained, anddimension b is wide enough for rapid drainage of pool II at the end ofteeming, to the same end, i. e., so that there will `be no residualmetal to freeze and keep the plate from floating upon backpouring.Drainage of pool Il is assisted by the downward slope of shoulder 4,which serves the further advantageous function of throwing the sheets 8away from the mold walls.

For some purposes I prefer to make the upper surface of plate' 5dome-fshaped, as shown in Figs. 1, 3 and 4, as this minimizes splashingbefore pool II forms, and to provide the upper edges of the plate with afillet I3 to cause the metal to run smoothly from the plate intopassageway a.

Various otherA advantages are also conferred.

Thus, by using an imperforate plate spotting of the ladle will notaffect the results, contrary to what was encountered with the feeder ofmy aforesaid patent. The clearance space a of substantial width betweenthe plate and the hot top walls permits `the float plate to be tiltedand lifted by tongs from the hot top. after the latter has been filledas shown in Fig. 4, so that it may be .reused with another hot topmember 2, thus reducing the expense of hot topping. Or, as may bepreferred in some instances it may be allowed to remain in place for thepurpose of keeping the body l2 of metal within the hot top molten to.insure maximum reduction of piping.

An advantage of the form of hot top shown in Figs. l1 to 4 is that theoperator can view the interior of the mold through the space between anouter wall of the hot top and the adjacent; mold than the head of stream9 from nozzle 6. Thus,

there is reduced agitation of the body I Il of molten metal within themold as compared with the stirring which would result if the main stream9 enters the mold directly. For the' same reason the rate of cutting outVof the stool 4is reduced substantially, stickers are reduced oreliminated, splashing in the mold of such intensity as to produce scabbysurface is avoided, and slag or other non-metallic material carried bythe metal in the ladle has full-opportunity to rise to the surface4 ofthemetal within themold. 'I'hese factors cooperate to improve the ingotquality. f

The ingot is teemed until drainage of pool I I will immerse the lowerend of the hot top within wall and thus determine when the metal hasbeen poured to the proper height, which is not possible, or at least notconvenient, with some forms of hot tops. v

Various modifications are, of course, permissible without departingfromthe spirit of the invention. For example, 'I now prefer Ato locatebosses 1 at the corners of the hot top to avoid the interference orturbulence that might occur otherwise at the corners by running togetherof the streams flowing over the sides of plate 5. Also, there may beprovided at least two other b osses la, Figs. 1 and 2, disposedcentrally of two opposed lengths vof shoulder 4, to provide adequatesupport in case of damage to one or more of the plate. Thus, Figs. and 6show a hot top 2p in which a plate Ia is supported above a shoulder laby bosses I4, integral with the plate, which hold the edges of the plateabove the shoulder by a distance b which is less than that of the sidepassageway a. Again, Figs. 7 and 8 show a hot top 2b in which the same ato b relationship is provided, but here plate 5b is supported overrashoulder Ib whose upper surface is hori- 4lrontal and the sides of whichare provided with centrally disposed bosses lb.

as applied to small-end-up molds of generally rectangular cross sectionit is to be understood that it is applicable generally-to ingot castingirrespective of the type of mold or its cross sectional character.

In addition to eliminating the formation of surface scabs the inventionotherwise improves the surface quality of ingots. Thus, in ordinaryprac,

tice the heavy head of metal from the nozzle coupled with therelatively, small area. of the mold Vopening causes the metal in themold to surge l upwardly'along the mold sides above the natural level ofmetal in the mold.. The thin skin of metal forced up the side ofthe moldin this manner freezes so quickly that contraction of it may causecracks to form which impair the surface of the ingot. Suchcracks mayextend asmuch as several inches into the ingot and effect the quality oiproducts made from it. In the practice of the present invention'themetal enters the moldunder such a low head pressure that there islittle or no tendency for suchsurface cracks to form.

described with reference to an i erforate float plate, it will beuifderstoo'd that hevplate may be perforated without encounteringdisadvantages of the feeder of ,the aforesaid patent bel causev thefeeder of this invention provides forl free drainage of metal around thesides ofthe plate so that the plate can not freeze in the bottom of thefeeder. Of course, the hot top should be positionedat such a level inthe mold, or the end of the hot top, that when the mold has been filledto its normal height the plate will be above the metal level, as -shownin Fig. 1. and thus willnot be frozen in place during the freezing in ofthe hot topby solidication of the surface metal between the hot top andthe mold. This may be accomplished, if need be, by appropriate.

blocking up of the hot `top by wooden blocks lj,

any case'to avoid hanger cracks,.as shown in F18. 1f A s. 9 and 10illustrate another modification in which the hot top 2c receives arefractory iloat- -pla lc which is smaller than theopening formed by theshoulder 4c but'which is supported by bosses 1c integral with theshoulder.l A s may be seen from Fig. 10, the distance b between thesides 'of platesel and the edge 'of shoulder 4c is substantially lessthan the distance s between the; hot top walls and the' sides of thefloat plate. Hence, and in accorda-nce with the invention, the-vAlthough the invention has been illustrated Although the invention hasbeen illustrated and s. An mgotcasting metal poured to such a heightabove the bottom i in accordance with a practice commonly used in topto. provide therebetween s substantial width for molten metal pouredinto the .hot top. and bosses integral with said shoulderto support saidjplate'va'b'ove and lwith its- 'shoulder a distance less Y f .than thewidthof said passageway. 70 5. An ingot Vcasting apparatus may be had bybosses formed on' the under side purposes be high enough to support theplateslightlyabove the lower edge of the shoulder, as shown in Fig. 10.

. Another desirable modification is shown in 5 11i This shows the hottop 2d provided with a side of the shoulder and thus to reduce theweight .10 of the hot top, its cost, and shipping charges.l Oblviou'sly, this modiiication is applicable to all forms of hot topswithinthe scope of this invention.

According to the provisions of the patent statutes I have explained theprinciple and modeof l5 use of my invention and have illustrated and de.

scribed what I now consider to represent its best enibodiment. However,I desire to have it understood that, within the scope of the appendedclaims, the invention may be practiced otherwise than as specicallyillustrated and described.

I claim: 1. An ingot casting apparatus comprising a tubular refractoryhot top having at its lower end a substantialLv continuous and inwardlyprojecting shoulder member adapted to support a plate member, arefractory plate member disposed within said hot top with its sidesspaced from the walls of the hot top to provide a passageway ofsubstantial width for molten metal 'poured into the hot top-to passtherebetween, and one of said members being provided with means spacingthe sides of the plate from said shouldera distance less than the widthof said passageway.

2. An ingot casting apparatus comprising a tubular refractory hot 'topprovided at its lower eng with a continuous inwardly projecting shouldermember, a. refractory plate-member disposed within said hot top with itssides spaced from the I walls of the hot topv to provide therebetweenapassageway of substantial width for molten metal poured into the hottop, and one of said members being provided with bosses for supportingthe plate at a distance froml said shoulder less than the width of saidpassageway.I e

tubular -refractory hot top provided at its lower end with- `9,continuous inwardly projecting and downwardly 'sloping shoulder member,a refractory plate member disposed within said hot top Fifi with itssides spaced from the walls of the hot top to provide therebetween apassageway of substantial width for molten metal poured into the hottop, and said shoulder member being4 provided with spaced bosses forsupporting the plate no at a distance from said shoulder less than thewidth of said passageway. l 4. An ingot. casting apparatus comprising arefractory tubular hot top adapted to be carried by the top of .a moldto form a continuation thereno -1- of, `said hot topv having at itsvlower end.v a .con-

tinuous inwardly projecting shoulder,- a refrac- 1. tory plate'memberdisposed. within Vsaid .hot top with its sides spaced from' me walls ofme l not a passageway of sides spaced from the 'All asubstantlallycontinuous and inwardlyprojectapparatus `comprising aaccording, to

fractory tubular hot top adapted to-be carried by the top of a mold,said hot top having at its lower end a continuous inwardly projectingshoulder, a refractory plate member disposed within said hot top withits sides spaced from the walls of the hot top to provide therebetween apassageway of substantial width for molten metal poured into the hottop, and bosses integral with said shoulder at the corners of the hottop to support said plate above the shoulder a distance less than thewidth of said passageway.

'8. An apparatus according to claim 1, said plate being imperforate andsaid shoulder sloping downwardly and inwardly from the hot top walls.

9. An apparatus according to claim 2, said plate being imperforate andsaid shoulder sloping downwardly and inwardly from the hot top walls.

10. An apparatus according 'to claim "l, -said plate being imperforateand said shoulder sloping downwardly and inwardly from the hot topwalls.

11. The combination withan ingot mold of a tubular refractory hot topforming a continuation of the mold, said hot top having at its lower enda substantially continuous and inwardly projecting shoulder member, arefractory imperforate plate member .disposed within said hot top withits sides spaced from the walls of the hot top to provide therebetween apassageway of substantial width for molten metal poured into the hottop, and one of said members being provided with vbosses for supportingsaid plate spaced from said shoulder a distance less than the width ofsaid passageway.

12. That method of casting ingots which comprises supporting from thetop of an ingot mold a tubular refractory hot top having at its lowerend a .continuous inwardly projecting shoulder.

, disposing in said hot top a refractory plate member with its sidesspaced from the hot top walls to provide therebetween a passageway' ofsubstantial Width, supporting said plate at a distance from saidshoulder less than the width of said passageway, pouring metal into saidhot top to form a pool of the metal therein while permitting metal toowintoV said mold through said passageway and the lesser space betweensaid plate and shoulder, discontinuing pouring and allowing the metalofA said pool to drain `into the mold, to immerse the lower end of thehot top in the metal, and thereafter pouring further metal into Said hottop t0 ll 1t and oat.

